On Mon, Mar 06, 2017 at 09:03:26PM -0800, Davidlohr Bueso wrote:
> +static __always_inline int
> +__range_read_lock_common(struct range_rwlock_tree *tree,
> + struct range_rwlock *lock, long state)
> +{
> + struct interval_tree_node *node;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&tree->lock, flags);
> + lock->reader = true;
> +
> + if (!__range_intersects_intree(tree, lock))
> + goto insert;
> +
> + node = interval_tree_iter_first(&tree->root, lock->node.start,
> + lock->node.last);
> + while (node) {
for (node = interval_tree_iter_first(); node;
node = interval_tree_iter_next()) {
Or some interval_tree_for_each helper?
> + struct range_rwlock *blocked_lock;
> + blocked_lock = range_entry(node, struct range_rwlock, node);
> +
> + if (!blocked_lock->reader)
> + lock->blocking_ranges++;
Can this @blocked range now go EINTR and remove itself from
wait_for_ranges()? If so, who will decrement our blocking_ranges?
> + node = interval_tree_iter_next(node, lock->node.start,
> + lock->node.last);
> + }
> +insert:
> + __range_tree_insert(tree, lock);
> +
> + lock->task = current;
> + spin_unlock_irqrestore(&tree->lock, flags);
> +
> + return wait_for_ranges(tree, lock, state);
> +}
